The present invention relates to a pressure detecting apparatus and more particularly to a pressure detecting apparatus mounting electronic parts for reducing electric disturbance.
A conventional pressure detecting apparatus, for example, as described in Japanese Application Patent Laid-open Publication no. Hei 10-170380, is a 2-chip sensor unit composed of a semiconductor sensor chip for converting a physical quantity to an electric signal and a semiconductor circuit chip for carrying out operations for a sensor output signal and obtaining a detection signal. The 2-chip constitution is a structure that the aforementioned semiconductor circuit chip is arranged on the lead frame, sealed with resin, thereby constitutes a package partially having a cavity, and the sensor unit that the semiconductor sensor chip is arranged in the cavity and electrically connected is arranged in the concave opening of the external case which is formed integratedly with the lead material having the concave opening and partially the connector terminal which is partially exposed into the concave opening, and the lead material is electrically joined with the lead frame, and then the package is closed with the cover.
However, in a conventional sensor unit of 2-chip constitution, when the user-required specification for transient voltage resistance and electromagnetic resistance is graded up more severely, a conventional semiconductor chip may not meet with the specification. If this occurs, it is necessary to re-design a customized chip and respond to it and a problem arises that many man-hours and expenses are required.
The present invention is intended to provide a pressure detecting apparatus capable of easily responding to specification changes.
(1) To accomplish the above object, the present invention has a lead material partially having a connector terminal for electrical connection with the outside, an external case partially having an opening which is formed integratedly with the lead material, a sensor unit composed of a semiconductor sensor for converting pressure to an electric signal, a signal processing circuit, an output terminal for outputting the processed signal, and a chip case partially having an opening as main component parts, and an electronic part for reducing electric disturbance, and a part of the lead material is exposed into the opening of the external case, and the sensor unit and electronic part are arranged in the opening of the external case, and the lead material, electronic part, and terminal of the sensor unit are electrically connected to each other in the opening of the external case.
By use of this constitution, the present invention can easily respond to specification changes.
(2) In (1) mentioned above, it is preferable that the external case is provided with a pressure introduction hole interconnecting with the opening of the external case, and the opening of the sensor unit and the opening of the external case are respectively provided with fitting parts, and the sensor unit and external case are fit into each other so that the semiconductor sensor of the sensor unit and the air introduction hole of the external case are interconnected with each other, and the sensor unit, electronic part, and exposed part of the lead material which are arranged in the opening of the external case are covered overall or partially with resin injected into the opening of the external case and integratedly fixed with injected resin, and the fitting part of the sensor unit and external case is sealed airtightly.
(3) To accomplish the above object, the present invention has a lead material partially having a connector terminal for electrical connection with the outside, an external case partially having an opening and a pressure introduction hole interconnecting with the opening which is formed integratedly with the lead material, and a sensor unit composed of a semiconductor sensor for converting pressure to an electric signal, a signal processing circuit, an output terminal for outputting the processed signal, and a chip case partially having an opening as main component parts, and a part of the lead material is exposed into the opening of the external case, and the opening of the sensor unit is arranged in the opening of the external case so as to interconnect with the pressure introduction hole, and the lead material and output terminal of the sensor unit are electrically connected in the opening of the external case, and the sensor unit and exposed part of the lead material arranged in the opening of the external case are covered overall or partially with resin injected into the opening of the external case, and the sensor unit and external case are integratedly fixed with the injected resin.
By use of this constitution, the present invention can easily respond to specification changes.
(4) In (1) or (3) mentioned above, it is preferable that the semiconductor sensor of the sensor unit is an absolute pressure sensor having a reference pressure chamber, and the semiconductor sensor for converting the pressure of the sensor unit to an electric signal and the signal processing circuit are composed of one chip, and the electronic part is composed of chip parts such as a capacitor and a resistor, and the external case is composed of thermoplastic resin, and resin to be injected into the opening of the external case is composed of thermoset resin, and the coefficients of linear expansion of the aforementioned thermoplastic resin and thermoset resin are set within the range from 20 to 40 ppm/xc2x0 C.
(5) In (1) or (3) mentioned above, it is preferable that the output terminal of the sensor unit and the lead material of the external case are electrically connected by welding, and a hollow is formed in the electronic part arrangement portion of the lead material, and a partition or groove for separating the hollows of different lead materials is formed in the external case, and the electrode parts of the electronic parts arranged in the hollows of the lead material are electrically connected with a junction member.
(6) In (5) mentioned above, it is preferable that the welding electrode arrangement area between the lead material of the external case and the output terminal of the sensor unit and the electronic part arrangement area are separated from each other without coexisting.
(7) In (1) or (3) mentioned above, it is preferable that at least three lead materials are used and when the electronic part is arranged so as to extend across the lead materials, the lead materials to be extended across are bent in a crank shape and embedded in the resin of the external case or the lead materials to be extended across are made thinner, and the electronic part arrangement portion of the lead materials is partially made wider.
(8) In (1) or (3) mentioned above, it is preferable that the neighboring portion of the opposite end to the connector terminal portion of the lead material integratedly formed with the external case is bent almost at right angles and the coaxial portion of the connector terminal in the opening and the two surfaces perpendicular to it are exposed into the opening of the external case.
(9) In (1) or (3) mentioned above, it is preferable that the end face of the opening of the sensor unit and the arrangement surface of the output terminal are different from each other and on at least one part between the contact surface with the end face of the opening of the sensor unit of the external case and the arrangement surface of the lead material electrically joined to the output terminal, an inclined surface is provided.
(10) In (1) or (3) mentioned above, it is preferable that a cover having a fitting part into the sensor unit or a part of the external case which is arranged so as to block the opening of the external case overall or partially is provided and the cover, sensor unit, and external case are integratedly fixed with injected resin.